The disclosure relates to a method for operating a hydraulic braking system of a motor vehicle, wherein the braking system comprises at least one wheel brake, a brake pedal device and at least one pressure generator that can be controlled so as to hydraulically actuate the wheel brake, and also an electromechanical actuator that is allocated to the wheel brake so as to actuate the wheel brake, wherein a force for displacing a brake piston of the wheel brake so as to actuate said wheel brake can be generated in each case by means of the pressure generator and actuator, wherein in order to enable a parking brake function the pressure generator and the actuator are controlled in such a manner that said pressure generator and actuator together generate a total clamping force at the wheel brake, and wherein an operating current of the actuator is monitored during the enabling procedure in order to determine the functional capability of the hydraulic braking system.
Methods, devices and braking systems of the type mentioned in the introduction are already known from the prior art. By way of example, German patent application DE 10 2010 040 573 A1 discloses a braking system of the type mentioned in the introduction having a hydraulic pressure generator and an electromechanical actuator that are simultaneously controlled so as to adjust a parking brake. In order to monitor whether the hydraulic part of the braking system is functioning correctly, a characteristic variable of the actuator is monitored and checked for inconsistencies. In the event of a current curve of the actuator lying outside a permissible value range, a malfunction is detected. This is by way of example the case if the hydraulic assistance fails and as a consequence the actuator requires more force in order to displace the brake piston so that as a consequence the operating current of the actuator increases above an expected value.